Management of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: Review and a Single Center Experience

A multi-lesional analysis of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: a single-centre analysis

AIM

To conduct a multi-lesional computed tomography (CT) analysis of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) patients to determine volumetric changes in lesions over 5 years.

MATERIALS AND METHODS

A retrospective case-note review was undertaken to identify 16 patients with histological and radiological features of DIPNECH between 2012-2021. Area and volume were calculated for 17 sets of lesions identified on high-resolution CT. Clinical data were extracted from electronic patient records, which included demographic data, outpatient clinic letters, histology reports, and imaging reports.

RESULTS

One hundred and twenty-eight lesions were identified in 16 patients (one male, 15 female) and followed-up annually over a median 1,985 days (range 1,450-2,290). At year 1 follow-up, lesion area ranged from 1-48 mm2, and lesion volume ranged from 8-18,380 mm3; lesion area ranged from 1-45mm2 and lesion volume ranged from 11-17,800 mm3 and year 5. Half (8/16) of the patients had concomitant typical carcinoid tumours and one patient had an atypical carcinoid tumour. No statistically significant correlation (p<0.05) was found between lesion cross-sectional area or volume and duration of follow-up (years and days). No metastatic spread was observed at the time of analysis.

CONCLUSIONS

No significant increase was observed in the size of over 100 lesions in patients with DIPNECH over a 5-year period and no metastasis occurred during the study period affirming the relatively indolent course of the disease.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: an under-recognized entity-a report of two cases

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary disorder that is classified as a pre-invasive lesion. It can also be present in association with chronic lung diseases. We present two cases of DIPNECH, which were picked up incidentally only on histopathology. A 29-year-old male presented with a history of longstanding cough with expectoration. A computed tomography (CT) scan showed bronchiectasis in the left lung. Histopathological evaluation of the pneumonectomy specimen revealed nests of proliferating, non-infiltrating neuroendocrine cells. Our second patient was a 38-year-old female with chronic cough and expectoration with recent exacerbation. CT scan showed cystic bronchiectasis in the left lower lobe; hence, a lobectomy was performed. On histopathology, nests of non-infiltrating neuroendocrine cells were noted. A diagnosis of DIPNECH with bronchiectasis was offered to both patients, and they have been on follow-up ever since. DIPNECH is a diagnostic and therapeutic quandary requiring a high index of suspicion for its detection and effective surveillance.

Pulmonary Function Tests as a Biomarker in Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia Patients Treated With Somatostatin Analogues

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) describes an indolent, under-recognised and poorly understood pulmonary condition with fewer than 200 reported cases across the literature. Currently, cases are diagnosed following a biopsy of the primary lesion, with treatment options centring on symptomatic benefit as opposed to targeting the underlying aetiology. Classically, DIPNECH lesions have been described as slow growing and benign, but with growing awareness of the condition, reports of metastatic disease with significant symptomatic burden have been reported. However, effectively addressing the subset of DIPNECH patients with greater metastatic potential remains an unmet clinical need. Due to the similarities between DIPNECH and carcinoid patients, several centres have considered using somatostatin analogues to not only help symptomatically but also to initiate tumour regression. However, to date, there are limited biomarkers to help evaluate the benefit of such options. In this review, we consider the use of pulmonary function tests (PFTs) to help quantify the benefit of somatostatin analogues. Although much of the evidence stems from small single-centre studies, the use of PFTs within the treatment pathway for both localised and metastatic DIPNECH represents a meaningful improvement from subjective monitoring of disease.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia presenting as a solitary lung nodule: a rare histopathological diagnosis

We present a case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) in a 56-year-old woman, who presented to our emergency department with a 7-day history of exertional dyspnoea. Due to profound haemodynamic compromise, pulmonary embolism (PE) was suspected, and the patient underwent emergency thrombolysis on admission. A subsequent computerized tomography pulmonary angiogram revealed extensive bilateral PE. Incidentally, a 1.3 cm lesion within the right upper lobe, associated with pleural tethering, was identified. Positron emission tomography computerized tomography and, subsequently, histopathology revealed this lesion to be primary DIPNECH, a rare pre-invasive hyperplasia of neuroendocrine cells. While studies are scarce and cohort numbers are low, somatostatin analogues and protein kinase inhibitors have been proven to reduce symptoms and increase progression-free survival in DIPNECH, respectively.

Prognostic Significance of Pulmonary Multifocal Neuroendocrine Proliferation With Typical Carcinoid

BACKGROUND

The clinical significance of multifocal pulmonary neuroendocrine proliferation (MNEP), including tumorlets and pulmonary neuroendocrine cell hyperplasia, in association with typical carcinoid (TC), is still debated.

METHODS

We evaluated a retrospective series of TC with long-term follow-up data prospectively collected from 2 institutions and compared the outcome between TC alone and MNEP plus TC. Several baseline covariates were imbalanced between the MNEP plus TC and TC groups; therefore, we conducted 1:1 propensity score matching and inverse probability of treatment weighting in the full sample. In the matched group, the association of clinical, respiratory, and work-related factors with the group was determined through univariable and multivariable conditional logistic regression analysis.

RESULTS

A total of 234 TC patients underwent surgery: 41 MNEP plus TC (17.5%) and 193 TC alone (82.5%). In the MNEP plus TC group, older age (P < .001), peripheral tumors (P = .0032), smaller tumor size (P = .011), and lymph node spread (P = .02) were observed compared with the TC group. Relapses occurred in 8 patients in the MNEP plus TC group (19.5%) and 7 in the TC group (3.6%). After matching, in 36 pairs of patients, a significantly higher 5-year progression-free rate was observed for the TC group (P < .01). Similar results were observed using inverse probability of treatment weighting in the full sample. The odds of being in the MNEP plus TC group was higher for those with work-related exposure to inhalant agents (P = .008), asthma or bronchitis (P = .002), emphysema, fibrosis, and inflammatory status (P = .032), or micronodules on the chest computed tomography scan and respiratory insufficiency (P = .036).

CONCLUSIONS

The association with MNEP seems to represent a clinically and prognostic relevant factor in TC. Hence, careful preoperative workup, systematic pathologic evaluation, including nontumorous lung parenchyma, and long-term postoperative follow-up should be recommended in these patients.

Well-Differentiated Bronchopulmonary Neuroendocrine Tumors: More Than One Entity

INTRODUCTION

Until now, well-differentiated bronchopulmonary neuroendocrine tumors (bpNET) occurring either sporadically (sp-bpNET) or in the context of multiple endocrine neoplasia type 1 (MEN1) and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) are regarded as similar entities. However, in contrast to sp-bpNET: MEN1-related and DIPNECH-related bpNET rarely metastasize or lead to bpNET-related death. We aimed to describe and compare the course of the disease of sp-bpNET, DIPNECH- and MEN1-related bpNET.

METHODS

All patients with histologically confirmed MEN1-related bpNET from the DutchMEN Study Group database (1990-2017), patients with resected sp-bpNET and DIPNECH patients referred to a Dutch European Neuroendocrine Tumor Society center between 2000 and 2018 were included. Fisher's exact test was used for comparison between groups. The primary end point was disease-specific mortality (DSM). Kaplan-Meier and logrank test were used to compare survival. Cox regression was used to identify risk factors for DSM in the sp-bpNET subgroup.

RESULTS

We included 112 sp-bpNET, 29 MEN1, and 27 DIPNECH patients. Tumor classification was similar across subgroups. A total of 20 patients (18%) with sp-bpNET died because of bpNET, compared with none in the MEN1 group and DIPNECH group. Median disease-specific survival was 12.3 (confidence interval: 6.3-18.3) years for patients with sp-bpNET, and not estimable for the other subgroups (p < 0.001). Differences in baseline characteristics did not explain worse survival in sp-bpNET. Tumor classification and age at diagnosis were independent risk factors for DSM in sp-bpNET.

CONCLUSIONS

Patients with sp-bpNET have a significantly higher DSM compared with MEN1 or DIPNECH-related bpNET, unexplained by differences in baseline characteristics. This implies that not all bpNET are similar entities.

Long-Term Imaging Follow-Up in DIPNECH: Multicenter Experience

Diffuse pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pre-invasive disease whose pathophysiology remains unclear. We aimed to assess long-term evolution in imaging of DIPNECH, in order to propose follow-up recommendations. Patients with histologically confirmed DIPNECH from four centers, evaluated between 2001 and 2020, were enrolled if they had at least two available chest computed tomography (CT) exams performed at least 24 months apart. CT exams were analyzed for the presence and the evolution of DIPNECH-related CT findings. Twenty-seven patients, mostly of female gender (n = 25/27; 93%) were included. Longitudinal follow-up over a median 63-month duration (IQR: 31–80 months) demonstrated an increase in the size of lung nodules in 19 patients (19/27, 70%) and the occurrence of metastatic spread in three patients (3/27, 11%). The metastatic spread was limited to mediastinal lymph nodes in one patient, whereas the other two patients had both lymph node and distant metastases. The mean time interval between baseline CT scan and metastatic spread was 70 months (14, 74 and 123 months). Therefore, long-term annual imaging follow-up of DIPNECH might be appropriate to encompass the heterogeneous longitudinal behavior of this disease.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: DIPNECH

PURPOSE OF REVIEW

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare premalignant condition. Over the past decade, there has been increased recognition and reporting of DIPNECH in the literature. Currently, our understanding is that DIPNECH has a predilection to nonsmoking females around their sixth decade of life. The patients usually present with chronic cough, dyspnea, and computed tomography (CT) showing multifocal pulmonary nodules with associated mosaic attenuation. The clinic history is largely driven by constrictive obliterative bronchiolitis, which typically has an indolent course with progressive respiratory decline and difficult to treat symptoms.

RECENT FINDINGS

DIPNECH has been found to be associated with carcinoid tumors. Recent data has found that symptomatic DIPNECH patients respond to somatostatin analog (SSA). SSAs provide improvement in symptoms and pulmonary function tests. According to small studies and case series SSAs can be used in conjunction with steroids and bronchodilators for the treatment of respiratory symptoms.

SUMMARY

DINPNECH is a premalignant condition that can transform into carcinoid tumors. Although the recent data suggest the potential efficacy of SSA, further studies are needed to validate such results in prospective fashion in addition to investigating other therapeutic agents.

An Update on the Management of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH)

OPINION STATEMENT

DIPNECH is caused by an idiopathic proliferation of pulmonary neuroendocrine cells which can lead to bronchiolitis and multifocal lung neuroendocrine tumors. Patients often present with chronic cough and dyspnea. Larger NETs may develop malignant potential. Somatostatin analogs can palliate chronic symptoms, particularly cough. Surgical resection can be considered for relatively large (e.g. >1 cm), progressive tumors.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: Imaging and Clinical Features of a Frequently Delayed Diagnosis

OBJECTIVE. The purpose of this study was to assess features of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) on CT, clinical presentation, and delays in radiologic and clinical diagnosis in a series of 32 patients. MATERIALS AND METHODS. Medical records of patients with DIPNECH from the years 2000-2017 were obtained from an institutional data warehouse. Inclusion criteria were an available CT examination and either a pathologic diagnosis of DIPNECH or pathologic findings of multiple carcinoid tumorlets or carcinoid tumor with CT features suggesting DIPNECH. Two thoracic radiologists with 10 and 14 years of experience reviewed CT examinations and scored cases in consensus. RESULTS. All 32 patients were women, and most had never smoked (69%). The mean age at presentation was 61 years. Symptoms included chronic cough (59%) or dyspnea (28%), and the initial clinical diagnosis was asthma in 41%. DIPNECH was clinically suspected at presentation in only one case and was mentioned by the interpreting radiologist in only 31% of cases. CT characteristics included numerous nodules with a lower zone and peribronchiolar predominance, mosaic attenuation, and nodular bronchial wall thickening. Number of nodules at least 5 mm in diameter showed strong inverse correlations with the percentage predicted for both forced vital capacity and forced expiratory volume in 1 second and a moderate inverse correlation with total lung capacity percentage predicted. In cases with a follow-up CT interval of 3 years or longer, 85% of patients showed an increase in size of the largest nodule, and 70% had an increase in size in multiple nodules. CONCLUSION. Many cases of DIPNECH are originally missed or misdiagnosed by radiologists and clinicians. Awareness of the typical clinical and imaging features of DIPNECH may prompt earlier diagnosis of this condition.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: A Clinical Case

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary condition characterized by diffuse proliferation of neuroendocrine cells in the epithelium of the bronchial wall. DIPNECH may be easily missed in daily clinical practice and diagnosis is often delayed, which may impair prognosis since this condition is considered a pre-invasive lesion for lung carcinoid tumours. We report a clinical case of DIPNECH in order to discuss the diagnostic and therapeutic approach for this entity, the management of which is not yet well established in the literature.

[A case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) syndrome]

INTRODUCTION

DIPNECH is a strictly histological entity according to the WHO 2015 classification and is considered to be at pre-neoplastic risk. It has been proposed that DIPNECH syndrome should be used to describe patients have clinical symptoms, an obstructive ventilatory disorder and compatible radiological abnormalities. The diagnosis is histological and usually based on a surgical lung biopsy.

CASE REPORT

We report the case of a 58-year-old woman with a chronic cough for over 20years who had an obstructive airway pattern on spirometry. Diagnoses of asthma and COPD had been discussed. After 7years of follow-up, the DIPNECH hypothesis was evoked on the scanning aspect of mosaic attenuation, expiratory trapping and micronodules, which was subsequently confirmed by surgical pulmonary biopsy.

CONCLUSION

It is necessary to consider the possibility of this rare disease in order to avoid inappropriate treatments and in the hope that future therapeutic advances (somatostatin analogs, mTOR inhibitors) improve patients' experience and the progression of respiratory function.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) with liver metastases

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) is a rare pulmonary disorder characterised by classic radiological findings and symptoms of obstructive lung disease. DIPNECH is considered a precursor to carcinoid tumours in the lungs. In this case, we describe a patient with years of unexplained dry cough presenting with 2 weeks of progressive nausea and vomiting, and found to have massive hepatomegaly on examination. By CT-PE, she was diagnosed with DIPNECH, and abdominal MRI revealed metastatic carcinoid tumours. Despite its non-specific presentation, DIPNECH has characteristic radiological findings of mosaic attenuation with numerous pulmonary nodules. DIPNECH requires early identification and close surveillance to prevent progression to carcinoid tumours. Thus, it is critical for frontline providers to consider this diagnosis as part of their differential when other common causes of obstructive lung disease have been ruled out.